WASHINGTON (Reuters) - The U.S. Food and Drug Administration on Tuesday said it would allow the Plan B One-Step contraceptive to be sold without a prescription to girls as young as 15 years of age.

The announcement partially reverses a December 2011 decision that prevented the sale of the emergency contraceptive to all females of reproductive age, which was also overturned by a U.S. district judge in New York on April 5. The FDA said its approval was not related to the judge's ruling.

Instead, the agency said it was responding to an amended marketing application from Teva Women's Health Inc, a unit of Plan B maker Teva Pharmaceuticals Industries Ltd. Teva originally applied to sell Plan B to all females of reproductive age, but changed its latest bid to those 15 and older after 2011. The amended application was pending when Judge Edward Korman handed down his ruling, the FDA said.

The pill known as "Plan B" has long been at the center of political and religious battles. The FDA initially approved sale of the drug to all reproductive age females, but was ordered to bar girls under 17 by U.S. Health and Human Services Secretary Kathleen Sebelius, who came under fire from women's activists who accused her of bowing to political pressure from social conservatives.

"Research has shown that access to emergency contraceptive products has the potential to further decrease the rate of unintended pregnancies," FDA Commissioner Margaret Hamburg said in a statement.

"The data reviewed by the agency demonstrated that women 15 years of age and older were able to understand how Plan B One-Step works, how to use it properly and that it does not prevent the transmission of a sexually transmitted disease."

The FDA said the product will now be labeled "not for sale to those under 15 years of age 'proof of age required' not for sale where age cannot be verified."

Product coding is designed to prompt cashiers to request and verify the customer's age. Teva has also arranged to have a security tag placed on all product cartons to prevent theft.

The U.S. Justice Department is considering the administration's next steps in the New York court case.